Livers on ice, which are destined for transplant, usually last for nine hours, and, if lucky, 12 hours. During this time, a lot of things should happen. First, the liver must be delivered from one hospital to another, while a surgical team is assembled. The operating room should also be prepped as a recipient is rushed into surgery, and the diseased liver should be removed with haste. It is a race against time as the liver deteriorates each hour on ice, and, if left on ice for too long, it won’t function in a human body again.

For this reason—along with the sobering statistic that 20 people die every day waiting for a transplant—doctors and scientists have long sought ways to preserve organs. Biologists now report a new strategy tested on five human livers: supercooling the organ to 4 degrees Celsius below zero, or just under 25 degrees Fahrenheit. This is below the freezing point of water, but the liver, perfused with a special solution, is never actually frozen. “When you touch it, it’s soft and there’s no ice,” says Shannon Tessier, a bioengineer now at Massachusetts General Hospital and co-author of the new study.

Preserved this way, the human livers appear viable, based on lab tests, for at least 27 hours. “That is impressive,” Ina Jochmans, a researcher and transplant surgeon at KU Leuven who was not involved in the study, wrote in an email.